Overview Assessment of the Potential Public Health, Environmental and Groundwater Resource and Other Impacts of the Proposed Adams Mine Site Landfill

Transcription

1 Overview Assessment of the Potential Public Health, Environmental and Groundwater Resource and Other Impacts of the Proposed Adams Mine Site Landfill Submitted by G. Fred Lee, PhD, PE, BCEE, F.ASCE G. Fred Lee & Associates El Macero, CA USA With the Assistance of Brian Gallaugher, BA, BES Gallaugher Associates Toronto, ON, Canada Revised December 12, 1995 Executive Summary Presented in this report is an overall assessment of the potential impacts of the proposed Adams Mine Site Landfill (AMSLF) on public health, groundwater resources, the environment and other interests within the potential sphere of influence of the proposed landfill. A summary of key issues is presented below. Public Participation in AMSLF Assessment Metro's public participation proposed landfill impact assessment process did not allow adequate time for peer and public review of many of the key issues that should be reviewed as part of completing the Phase 1 Assessment. Metro's consultants final reports were made available with inadequate time for review prior to the PLC meeting to which the peer reviewer reported to the PLC on his findings. It should, therefore, not be assumed that Metro's consultants final reports reliably and adequately address the peer reviewers comments on the draft reports. Potential for Groundwater and Surface Water Pollution by Landfill Leachate Adequacy of Existing Information. At this time there are significant technical deficiencies in the studies that have been conducted on the geology/hydrogeology and on current groundwater and surface water quality. These deficiencies significantly limit the reliability that Metro and its consultants can justifiably claim regarding the ability of the proposed landfill design, operation, closure and post-closure care to protect off-site pollution of groundwater and possibly surface water by landfill leachate for as long as the wastes in the landfill represent a threat.

2 While Metro and its consultants state "The site can be safely designed and operated as a landfill facility.", this is a premature assessment of the safety of the proposed landfill facility based on what is known today. At this time it can be indicated that it may be possible to develop a "safe" landfill facility at the Adams Mine Site. Hydraulic Containment Operations. A hydraulic containment mode of operation involving inward groundwater flow into the landfill where the groundwater and leachate are removed from the bottom of the landfill appears to be feasible. Substantial further work needs to be done to demonstrate the reliability of this mode of operation, however. Gravity Drainage Operations. There are also significant questions about the reliability of the socalled gravity drainage mode of operation that is proposed to be activated at the end of the contaminating lifespan in preventing leachate-derived constituents from polluting groundwaters of the region. Significant additional work needs to be done to demonstrate the reliability of both proposed modes of operation of the landfill. Service Life of Leachate Removal System. It appears that Metro's consultants may have overestimated the service life of key components of the leachate removal system. There is a significant potential for blockage of this system by biological growths and chemical precipitation that could impair the ability to maintain an effective hydraulic containment mode of operation that would prevent off-site groundwater pollution by leachate. Contaminating Lifespan. While Metro's consultants estimate that the contaminating lifespan of the proposed landfill will be on the order of 100 years, there are significant questions about the reliability of this estimate. Insufficient information was presented in the consultants' reports and cited references to justify the 100-year value. It is more likely that the contaminating lifespan of this landfill will be several hundred to a thousand years or more. If the contaminating lifespan exceeds the expected service life of key components of the leachate removal system, then this landfill may not be granted a license by MOEE based on its current proposed design. Leachate Generation Rates. Metro's consultants have underestimated the amount of moisture that will enter the landfill through the cover of the closed landfill. This will result in increased leachate production over that estimated. The ramifications of this increased leachate production have not been evaluated. Leachate Treatment. The proposed leachate treatment system has the potential to provide high degrees of leachate treatment that if properly operated and monitored could protect water quality within the Misema River. The proposed degree of treatment involving the use of a mixing zone for dilution of the hazardous and deleterious chemicals to concentrations below that allowed by MOEE should be increased in order to help protect Misema River water quality from potential adverse impacts of unregulated chemical constituents in the treated leachate. The leachate treatment system may need to be expanded to include additional treatment beyond that proposed to control potential adverse impacts associated with chronic aquatic life toxicity 2

3 and bioaccumulation of treated leachate-derived constituents to and within fish and other aquatic life in the Misema River. The flows of the Misema River relative to those of the projected leachate are such that a considerable natural safeguard exists from adverse impacts of the unregulated chemicals present in MSW leachate. It will be important to reliably monitor the treated leachate and the river for potential adverse impacts from these chemicals. Several of the current MOEE water quality standards for protection of aquatic life and human health are not adequate and need to be revised. The leachate should be treated to meet water quality protection standards which reflect the latest in reliable technical information on the impacts of chemicals on public health, aquatic life and wildlife. Disposal of Pit Dewatering Water. While it appears, at this time, that the water in the AMS pits can be safely discharged to the Misema River without treatment, the studies that have been conducted on the characteristics of these waters by Metro's consultants have not reliably evaluated all potential constituents or conditions that need to be evaluated prior to determining that it is safe to discharge the pit waters to the Misema River without treatment. One of the major problems is that some of the analytical methods used to investigate the characteristics of the pit waters, such as for arsenic, were not sufficiently sensitive to determine whether these waters had concentrations above MOEE standards. Further, no toxicity testing was done on these waters to determine if unregulated chemicals within them could be potentially toxic to aquatic life in the Misema River. It is possible that further studies could show that very expensive treatment of the pit waters would have to be carried out before discharge to the Misema River. Surface Water Quality Monitoring. A key component of the leachate treatment system will be the development and implementation of a water quality monitoring program that assesses the potential impacts of the residual regulated and unregulated chemical constituents in the treated leachate. At this time, Metro and its consultants have not proposed an adequate water quality monitoring program to protect aquatic life and other uses of the Misema River from residual chemical constituents in the treated leachate. Attention must be given to the potential impacts of the large number of unregulated organic chemicals in the treated leachate that could impact water quality in the Misema River. This is an area that has been largely ignored by Metro and its consultants thus far that will need to be addressed as part of Phase 2 of this Assessment. Groundwater Quality Monitoring. The groundwater quality monitoring program developed thus far by Metro and its consultants is deficient compared to the program that will ultimately be needed to try to detect pollution of groundwaters by leachate that could escape from the hydraulic containment system proposed by Metro for preventing groundwater pollution at the proposed Adams Mine Site Landfill. Metro should be required to develop a groundwater monitoring approach that will ensure a known high degree of reliability in detecting leachatepolluted groundwaters under the Adams Mine Site property before they trespass under adjacent properties. 3

4 Groundwater Production Well Monitoring. Further, Metro should be required to conduct groundwater monitoring of all production wells within the worst-case potential sphere of influence of leachate-polluted groundwaters that could develop at the Adams Mine Site Landfill for as long as the polluted groundwaters and landfill represent a threat. For planning purposes, this period of time should be considered to be infinite. This off-site production well monitoring should be conducted to detect incipient groundwater pollution by landfill leachate with a sufficient early warning so that this pollution is known before harm to the users of the water occurs. Third-Party Monitoring. Metro should fund a comprehensive third-party independent monitoring program for the landfill operations and environmental impacts in order to detect problem areas before they become significant. This third-party monitoring should be conducted in such a way as to supplement Metro's and the regulatory agencies' monitoring programs. The results of this monitoring program should be presented directly to a citizens advisory committee responsible for the oversight of the Adams Mine Site Landfill development, operations, closure and post-closure care. Worst Case Scenario Evaluation. The worst case scenario evaluation for pollution of groundwater by landfill leachate projects that appreciable local surface water pollution could occur in the vicinity of the landfill. Insufficient information is available at this time to be certain that this proposed worst case scenario has been, in fact, reliably developed. There may be other conditions that need to be incorporated into a worst case scenario evaluation. Remediation of Polluted Groundwaters. At this time, Metro and its consultants have given inadequate attention to defining possible remediation approaches that could be used for off-site as well as on-site groundwater pollution that might develop associated with the Adams Mine Site Landfill. A key part of the development of a "safe" landfill is the development of remediation approaches for polluted groundwaters that might under worst-case conditions develop at the landfill and be transported off-site to pollute adjacent property owners' groundwater supplies. Metro should as part of the Phase 2 Assessment program, should it proceed with the development of this landfill, define possible remediation approaches for both off-site and on-site groundwaters. These approaches should include a discussion of the remediation approaches that would be implemented if incipient Adams Mine Site Landfill leachate pollution is detected offsite to stop further pollution and to clean up the polluted groundwaters to the maximum extent possible. Funding of Remediation. A key part of development of the groundwater pollution remediation program will be the definition of the magnitude of the funding that could be needed for the program implementation and how Metro can assure that the funds will, in fact, be available in perpetuity to address contingency needs for possible groundwater pollution that could occur at the Adams Mine Site. These contingency needs could include removal of the wastes from the Adams Mine Site Landfill (landfill mining) if it is not possible to stop off-site pollution of groundwaters from this landfill. 4

5 Reasonable Use Policy. It is important in planning for a "safe" landfill to not utilize the MOEE Reasonable Use Policy approach which allows the contamination of groundwaters by leachate up to 25% to 50% of the Ontario Drinking Water Objective for health and non-health related parameters, respectively. This Policy fails to consider the presence of hazardous, unregulated chemical constituents in landfill leachate that could be transported through aquifers off-site. Any contamination of off-site groundwater by leachate (any presence of a leachate-derived constituent) should for public health and groundwater resource protection, be considered a situation that requires groundwater remediation independent of whether any drinking water objectives are exceeded. This is prudent public health policy and the approach to which the Adams Mine Site community and property owners-users of the region near the landfill should be entitled. Adequacy of MOEE Landfilling Regulations. The current MOEE landfilling regulations are deficient in several areas in protecting public health and the environment from adverse impacts of landfill derived constituents. In addition to the deficiencies associated with the reasonable use policy and some of the water quality objectives, one of the most important deficiencies is the failure of theses regulations allow to adequate bufferlands between the waste deposition areas and adjacent properties. Metro will likely have to purchase or gain easements from adjacent properties in order to dissipate adverse impacts of the proposed landfill associated with odor, dust and noise. Impact on Agriculture. While Metro's consultants claim that the proposed landfill will not be adverse to agriculture, thus far they have not presented convincing evidence on this issue. The work of Gartner Lee on the origin of the Temiskaming Little Clay Belt region groundwater shows that based on the information available now, there appears to be little likelihood that leachate polluted groundwaters that could arise in the vicinity of the proposed AMSLF would be transported to the Little Clay Belt region and thereby pollute groundwaters in the region. However, the TFA investigations have revealed that the Munroe esker could potentially be a pathway for transport of leachate polluted groundwaters to the Little Clay Belt region. This is an issue that must be adequately addressed so that the farming interests are confident that there is little likelihood of adverse impacts if this landfill is developed. Other Impacts Landfill Gas. There is a significant potential for on-site landfill gas problems associated with vinyl chloride emissions and groundwater pollution by VOC's. These problems could be manifested off-site. Odor. It is projected that there will be significant off-site odors from this landfill. It is not clear, however, that the projections have reliably estimated the full magnitude of these odors. While Metro's consultants assert that odor is only a nuisance, it is well known that highly offensive odors such as those associated with landfills can be detrimental to an individuals health. Metro will need to develop odor control approaches and acquire additional property for odor dissipation. 5

6 Dust. There will be potentially significant dust releases off-site, arising from landfill operations. At this time, inadequate attention has been given to the potential human health hazards associated with PM 10 particles in this dust. Noise. Metro's consultants discuss the potential for adverse impacts of landfill-derived noise and some other adverse impacts of emissions from the landfill at nearby property residences. It is the reviewers understanding that Metro will have to control adverse impacts at the landfill and adjacent property line. Adjacent properties should not be used to dissipate adverse impacts of releases from the landfill. Birds. The evaluation of potential bird problems at the proposed AMSLF is highly superficial and in some instances inaccurate. Without highly effective bird control programs, gulls and other birds could possibly become a problem at the proposed landfill through impacts on aviation and possibly through the transport of disease. On-Site 3R Activities. At this time the on-site 3R activities have not been defined. Of particular concern is the potential for outdoor composting and the control of odors associated with such composting activities. Potential Operation Issues. There are a number of potential operation problems that have not been adequately addressed. Of particular concern is the unloading of the rail containers during cold weather conditions. Economic Evaluation. The economic evaluations performed by Metro's consultant does not provide sufficient details to enable the peer reviewers' to evaluate the adequacy and reliability of the projected costs of landfilling at the proposed AMSLF. Of particular concern is the potential that the true cost of operation and especially post-closure care will be substantially higher than those projected. It is possible that these costs may add 10 to several 10's of dollars per ton to the disposal costs associated with the development and use of the proposed AMSLF. Further, the expected revenue associated with developing a landfill gas recovery system may have significantly overestimated the revenue that will in fact be generated by the recovery and use of landfill gas. Development of the AMSLF as a Waste Treatment System. Metro and its consultants have concluded that the shredding of the waste to enhance the hydraulic characteristics of the landfill and thereby reduce its contaminating lifespan is not justified. It appears, however, that an inappropriate analysis of this situation has been made. Metro needs to reevaluate the potential benefits of shredding the waste placed in the landfill and the addition of moisture to the landfill to enhance the rate of waste stabilization through conversion of many of the organics into landfill gas and the leaching of the waste to remove leachable components in a shorter period of time than will occur under the proposed mode of operation. Overall Assessment. Overall, at this time Metro and its consultants have not provided reliable and/or adequate information on the current state of knowledge on the impacts of the proposed Adams Mine Site 6

7 Landfill on off-site public health, groundwater resources and the interests of those within the potential sphere on influence of the landfill. While at this time no potential adverse impacts have been identified that would preclude the development of the Adams Mine Site Landfill so that it would be "safe" and a "good neighbor" to the owners and users of the lands near the landfill, there is need for considerable work to be done in Phase 2 of this Assessment and a high level of commitment by Metro to address contingencies if this landfill is to be developed with a high degree of certainty of full protection of public health, groundwater and the environment. It is likely that addressing what are now known and what could develop as potentially adverse impacts of the proposed AMSLF could significantly increase the cost of landfilling at this site from that currently projected by Metro and its consultants. Introduction Metropolitan Toronto (Metro) has proposed to construct a municipal solid waste (MSW) landfill in the Kirkland Lake, Ontario region that would accept approximately 40 million tonnes of waste over at least 20 years. Metro began conducting studies in 1990 devoted to evaluating the potential public health, groundwater resource, environmental and other impacts of this proposed landfill. The landfill is proposed to be constructed in three pits of the Adams Mine Site (AMS). Over the past six months Metro and its consultants have developed a set of draft reports covering their current findings on these impacts. A detailed set of comments has been provided by the author on each of these reports. This report provides an overview summary of the key findings, conclusions and recommendations on issues that should be considered by the Public Liaison Committee (PLC) in evaluating the appropriateness of developing Metro's proposed Adams Mine Site Landfill. The development of this proposed landfill was based on a potential willing host concept in which the host communities of Kirkland Lake, Larder Lake and Englehart entered into an agreement with Metro to support the development of this landfill in exchange for a royalty and other benefits that would be paid to these communities. While councils of these communities signed this agreement in 1990, there is a significant question today about whether such a referendum would be supported by the public. Some of the apparent public opposition to the development of the proposed AMSLF appears to be the typically-based Not-In-My-Back-Yard (NIMBY) approach. There has been and, in general, continues to be considerable justified NIMBY associated with the development of an MSW landfill in a region. The author has devoted considerable effort to understanding NIMBY as it relates to the development of MSW landfills and, most importantly, developing approaches that can be used to address justified NIMBY. Dr. Jones-Lee and he have published extensively on these issues. 7

8 The proposed AMSLF provides a unique opportunity where the host communities and others in the region have the opportunity to recommend to Metro, through the PLC, approaches that can potentially be used to address NIMBY issues. The development of the proposed AMSLF has the potential of being significantly different from most landfill development projects in that a voluntary host community was sought and the landfill owner, Metro, would not just meet but rather, in some instances, would exceed to some extent, the current minimum regulatory requirements for developing an MSW landfill. The author has provided the PLC with a detailed set of comments on some of the significant deficiencies in current Province of Ontario (MOEE) regulatory requirements for MSW landfill siting, operation, closure and post-closure care. Ordinarily, the public who face the siting of a landfill in their region are not provided with the support necessary to achieve a high degree of understanding of the technical issues associated with the siting, operation, closure and post-closure care of a proposed landfill in their region. However, the people of Ontario and especially in the Kirkland Lake area, have the assistance of qualified technical expertise to critically review Metro's consultants' reports and provide comments on technical deficiencies - inadequacies. The PLC, members of the public and others in the Adams Mine Site area have the potential benefits of Gartner Lee's - Bill Balfour's and his associates' expertise and experience as well as the expertise of Brian Gallaugher and the author in reviewing Metro's proposed approach for developing the AMSLF. Unfortunately, Metro's Phase 1 Assessment process has been conducted in such a way as to not allow adequate time for review of the key issues that should be reviewed before a decision is made about proceeding to Phase 2. As the author has indicated through the course of the peer review process, while there are many questions about the potential impacts of this proposed landfill, he has not, including to this time, encountered any issues that he feels require abandonment of the development of this proposed landfill based on its potential impacts on public health, groundwater resources, the environment and the interests of those within the potential sphere of influence of the landfill. All of the potential problems that have surfaced thus far can be addressed. It will be up to Metro and the people of Toronto to adopt adequate approaches that address the issues raised by Gartner Lee staff, the author, B. Gallaugher, PLC, and the public. Specific Comments Presented below are comments on problems with the approaches used for the development of the Adams Mine Site Landfill. Public Consultation. There were some significant deficiencies in the public consultation process. Some of Metro's consultants' reports did not provide a balanced, full disclosure discussion of potential environmental, public health and other impacts of the proposed landfill. Further, the overall process that was conducted for review of technical issues was inadequately planned to allow appropriate time for full peer and public review. The work plans that were developed for the various studies conducted by Metro's consultants did not provide sufficient detail to enable the peer reviewers to evaluate the adequacy of the proposed studies. Further, the review process did not include the opportunity for comments by the peer reviewers on the adequacy of the proposed approach. 8

9 In general, the consultants' reports were late compared to the timetable that was originally developed. As a result, for a number of these reports the peer reviewers had only a couple of days before their comments had to be submitted to meet the deadline established by Metro. The net result was inadequate time for both peer review and public input on some of the key issues that need to be addressed and resolved before proceeding to Phase 2 of the Assessment process. It will be important that if this process continues into Phase 2, a more appropriate planning and implementation of consultants' and peer reviewers' activities be developed so that information can be brought to the attention of the PLC and others with adequate time to conduct an in-depth, appropriate review of unresolved issues. One day before the final PLC meeting on December 10, 1995 at which the author was to present his conclusions on the adequacy of Metro's consultants review of the proposed AMSLF, Metro made available to the author about 2 feet of revised consultants reports. These reports were supposed to address, to some extent, some of the comments made by the peer reviewer and others in the draft reports that they reviewed and commented on. There was, obviously, insufficient time to determine whether Metro's consultants had adequately and reliability incorporated revisions into the final reports that addressed the concerns of the peer reviewer that arose from a review of the draft reports. It should not be assumed that Metro's consultants final reports have adequately and reliably addressed the peer reviewers's comments. A review of these issues will have to be conducted with supplemental funding as part of Phase 2 of the Assessment process, should Metro decide to proceed with further development of this landfill. Adams Mine Site Investigations. At this time, there are significant deficiencies in the studies that have been conducted regarding the Adams Mine Site geology/hydrogeology and groundwater and surface water quality that will need to be properly addressed in Phase 2 should Metro decide to go ahead with the studies. In some cases, these studies could show that some of the preliminary predictions of net environmental impacts based on Metro's and its consultants' statements of conclusions may be inappropriate. The peer reviewers found that Metro's consultants' reports frequently contained statements about the "safety" of a proposed approach for development of this landfill that were not supportable based on the information provided by the consultants. There are many instances where significant questions are raised by the peer reviewers about the reliability of the conclusions presented in the consultants' reports. It will be important that if further work is done in this Assessment, that Metro and its consultants provide detailed information on how they developed their conclusions on particular issues. These presentations should be in sufficient detail so the peer reviewers can develop the same conclusions from the information made available by the consultant as were developed by the consultants. Metro and its consultants asserted, "The site can be safely designed and operated as a landfill facility." This is a premature assessment based on what is known today. What can be said is that, from the information available, it appears that it may be possible to design, operate, close and provide post-closure care to protect public health, groundwater resources and the environment from the potential adverse impacts of the proposed landfill. Considerable additional work will need to be done, and the full cooperation of Metro in providing the necessary safeguards will be 9

10 required in order to state that the Adams Mine Site can be safely designed and operated as a landfill facility. While the author agrees that this is possible, it will take significantly different approaches on the part of Metro to develop safeguards than are conventionally provided in the design, operation, closure and post-closure care of municipal solid waste landfills. These additional safeguards will likely significantly increase the cost of landfilling at the proposed AMSLF over that projected by Metro and its consultants. As of yet, Metro has not indicated that it is willing to make this level of commitment. Reliability of Hydraulic Containment. Metro and its consultants have overstated the current understanding of the ability of hydraulic containment - inward groundwater flow at the site to keep leachate from traveling outward into the groundwater. While this appears to be possible, significant additional work will be needed to demonstrate more reliably that hydraulic containment can, in fact, be made to work at this site for as long as the wastes in the landfill remain a threat. Service Life of Leachate Removal System. There is significant potential that the landfill leachate removal system will plug due to biological fouling and chemical precipitation. This would greatly impair, if not block, the removal of leachate from the landfill due to blockage of the filter layer between the bottom of the wastes and the leachate drainage layer as well as within the leachate drainage layer. If blockage of the leachate removal system occurs, then leachate could build up in the landfill to the point where it could reverse the inward hydraulic gradient which could lead to groundwater pollution by leachate. Metro should reevaluate the possibility of removal of leachate from the landfill by in-waste pumping as a back-up to the proposed method of leachate removal. Contaminating Lifespan. Metro and its consultants state that the projected contaminating lifespan for the proposed Adams Mine Site Landfill will be on the order of approximately 100 years. They further state that after about 100 years, it will be possible to stop pumping leachate from the landfill leachate removal system and stop operating the leachate treatment system. At that time, the pits would be allowed to fill to a considerable extent with leachate. This leachate is proposed to be collected in a gravity drainage system. It is the author's assessment that at this time, the 100-year contaminating lifespan has not been reliably evaluated. Metro should plan for an indefinite contaminating lifespan, certainly a thousand years or more. Metro's consultants' calculations as well as what the author concludes on the contaminating lifespan of this landfill show that the leachate at the end of about 100 years could still be a significant threat to pollute groundwaters and surface waters if discharged without treatment. While perimeter drainage systems of this type are used in dewatering mines, there is a significant difference between dewatering for mining operations and the control of leachate pollution of groundwaters. Small amounts of MSW leachate have high potentials to pollute large amounts of groundwater impairing their use for domestic and other water supply purposes. It is essential in developing an assessment of the reliability of the hydraulic containment pumping and gravity drainage modes of operation, to consider how effectively all leachate will be collected. 10

11 Leachate Generation Rates. From the information available, it appears that Metro's consultants have underestimated the amount of leachate that will be generated in this landfill due to increased percolation of water through the cover of the landfill beyond the amount projected in calculating leachate generation rates. It is inappropriate to assume, as has been apparently done by Metro's consultants, that the design characteristics of the cover which determine the amount of moisture that enters the landfill and generates leachate during the contaminating lifespan of the landfill will remain constant as designed over the hundreds to thousand or more years that this landfill could be a threat to public health, groundwater resources and the environment. The increased moisture that will likely enter the landfill through the cover beyond the amount projected needs to be evaluated with respect to how it would impact the many components of leachate management that are discussed in Metro's consultants' reports. Rather than allowing leachate generation in the landfill to be controlled by unplanned changes in the permeability of the cover due to cracks that develop in the low permeability layer of the cover, Metro may find that installing a leak detectable cover on this landfill and a deliberate moisture addition system could be a significant asset in reducing the contaminating lifespan of the landfill. Leachate Treatment. Metro proposes to treat the leachate removed from the landfill and discharge the treated leachate to the Misema River. The leachate treatment system proposed is a good start on the approach for leachate treatment that will have to be followed. While it may be adequate for most conditions, there may be situations where additional treatment of the leachate may be necessary to protect public health, aquatic life and wildlife from residual constituents in the leachate. There are questions about whether this treatment system will operate year-round and whether the discharges of treated leachate will occur directly to the Misema River or to tributaries of the river. It is unclear whether the indirect discharge to the river will be on an intermittent basis where the treated leachate would be stored over the winter. These issues need to be resolved in order to determine the treated leachate loading to the river at various times of the year. The relative flows of the Misema River versus those projected for the treated leachate appear to be such that even under drought conditions there still could be appreciable dilution of the treated leachate by the river water. The proposed leachate management approach, therefore, has a natural safeguard of appreciable dilution built into it. It is important to maintain the magnitude of this safeguard in order to protect the aquatic resources of the river from impacts from the unregulated chemicals that are present in leachate. At this time, Metro proposes to treat the leachate for most constituents to within five times of the MOEE water quality objective and/or drinking water standard. Metro plans to use a mixing zone of up to one half the width of the Misema River and several hundred meters downstream of the discharge in which the excessive concentrations of constituents in the treated leachate, compared to MOEE objectives, will be diluted to concentrations equal to or less than the objectives. While this approach apparently would be accepted by MOEE, such an approach should not be allowed. There are situations, such as for bioaccumlatable chemicals i.e. mercury, where organisms could accumulate within their body tissue, excessive mercury concentrations within the mixing zone and thereby represent a hazard to those who use these organisms as food. 11

12 The primary reason for not allowing a mixing zone for hazardous chemicals in the treated leachate is that MSW leachate, after treatment, still contains a large number of potentially hazardous unregulated chemicals. By requiring that Metro treat the leachate so that it could be discharged to the Misema River without dilution for all regulated chemicals, it would be possible to reduce the hazards by a factor of five associated with the unregulated hazardous chemicals in the treated leachate. This is appropriate for this type of situation where complex mixtures of potentially hazardous chemicals are being discharged into a relatively pristine system - the Misema River. Under such conditions dischargers should be required to provide additional treatment beyond the minimum necessary to satisfy current regulatory approaches. The proposed approach of not allowing a mixing zone for potentially hazardous chemicals is in accord with the resolution adopted by the PLC at the December 10, 1995 meeting, of zero pollutant discharge from the leachate treatment plant to the Misema River. This resolution is appropriate and should be adopted. It is also important that Metro not attempt to use the existing MOEE policies - standards as the basis for development of this landfill where the minimum protection that these policies require represents the level of control that Metro will commit to in protection of the health, interests and welfare of those potentially impacted. For example, with respect to existing surface water quality, the current MOEE standard for mercury in water is well-known not to be adequate to protect pregnant women from harm due to eating fish which have been taken from waterbodies that have mercury at the currently allowed concentrations, based on PWQO's. Although it is not clear at this time that MOEE will require the treatment of the leachate so that it has no chronic toxicity to aquatic life at the point of discharge, Metro should commit to protecting aquatic resources so that there is no aquatic life toxicity as assessed by either acute or chronic toxicity measurements using several sensitive test organisms. In those instances where MOEE standards may not reflect the most current information available on the impacts of chemicals on human health, aquatic life and wildlife, Metro should treat the leachate in accord with the latest generally accepted reliable information for protection of public health, aquatic life and wildlife. Discharge of Pit Dewatering Waters to the Misema River. Metro's consultants conclude, based on the chemical characteristics in the three AMS pits that are proposed to be used as landfills, that this pit water can be safely discharged to the Misema River without treatment. However, a review of the adequacy of the studies conducted by Metro and its consultant of the characteristics of the pit waters, shows that there were significant deficiencies in some aspects of these studies. For example, the analytical methods used to measure arsenic in the pit waters was not sufficiently sensitive to detect arsenic at concentrations that are potentially adverse to Misema River water quality. Therefore, if the pit waters contained elevated levels of arsenic compared to drinking water standards, there is a potential that the discharge of pitwaters without treatment for the removal of arsenic could be adverse to the Misema River water quality. Similarly, the studies on the pit waters did not include any assessment of aquatic life toxicity or the bioaccumulation of hazardous chemicals in the fish that were taken from one of the pits. 12

13 These pit waters, therefore, could contain chemicals that could be toxic to aquatic life in the Misema River and/or could bioaccumulate within aquatic organisms in the Misema River. A more comprehensive evaluation of the characteristics of the AMS pit waters must be conducted before it can be concluded that these waters can be safely discharged to the Misema River without treatment and/or significantly altering the rate of dewatering of the pits from that proposed. Water Quality Monitoring. The groundwater and surface water monitoring systems proposed by Metro are significantly deficient compared to the programs that will be needed to ensure adequate protection of public health, groundwater resources, the environment and the interests of those who own or use properties within the potential sphere of influence of the proposed landfill. Of particular concern for surface water quality protection is the need to conduct chronic bioassays on the treated leachate effluent and the river waters. Also, there is need to conduct bioaccumulation studies on aquatic life within the river to ensure that excessive accumulation of potentially hazardous chemicals which represent a threat to public health and wildlife through the use of river organisms as food does not occur. The information provided on Metro's proposed approach for groundwater quality monitoring is nebulous and inadequate. Because of the great difficulties in reliably monitoring leachatepolluted groundwaters in fractured rock systems of the type that exist near the proposed Adams Mine Site Landfill, it will be necessary for Metro to develop a groundwater monitoring approach that provides a highly defined degree of reliability of detecting leachate-polluted groundwaters that exist under the Adams Mine Site property. The PLC and the public should be informed as to the reliability that Metro's proposed groundwater monitoring system has in detecting leachatepolluted groundwaters before crossing the Adams Mine Site Landfill property line. Since it will likely be difficult to develop a groundwater quality monitoring approach that will potentially detect leachate-polluted groundwaters with a greater than 95% probability under the Adams Mine Site Landfill property, it will be essential for Metro to develop an off-site groundwater quality monitoring program for all production wells that exist now or are developed in the future that are within the potential worst-case sphere of influence for leachate-polluted groundwaters to travel from the Adams Mine Site Landfill to an off-site well. This groundwater quality production well monitoring will need to be conducted for as long as the wastes in the landfill and any polluted groundwaters that may have developed associated with the landfill will be a threat to groundwater quality. For planning purposes, the off-site groundwater quality production well monitoring program should include monitoring of a variety of parameters with sufficient frequency and reliability to detect incipient groundwater pollution by leachatederived constituents before harm to the users of the well occurs. Because of the uncertainty and sometimes unreliability of both landfill operators' and regulatory agencies' monitoring of releases from landfills, this monitoring program should be conducted by a third-party independent monitoring group that is funded by Metro but reports directly to an Adams Mine Site Landfill citizens advisory committee that oversees the operations of this landfill. 13

14 Plausible Worst Case Scenario Evaluation. During the review of the Metro's draft consultant reports, the author suggested that Metro require that its consultants conduct a plausible worst case scenario evaluation for leachate management and then address how this situation would be detected, remediated, the amount of funds needed to control the problem and the source of the funds that would be needed at any time in the future for the remediation. At the December 9, 1995 Temiskaming Federation of Agriculture - PLC workshop, a Metro consultant presented, for the first time, a plausible worst case scenario failure for the hydraulic containment approach. He indicated that under this scenario, leachate that escapes from the landfill would come to the surface as a surface discharge near the landfill. This leachate then would drain to Boston Creek and the Misema River polluting both waterbodies. At this time, no details have been provided on the development of this worst case scenario and its reliability. It will be important, as part of Phase 2, to conduct an in depth review of this proposed worst case scenario to be certain that it is reliable and does in fact represent a true worst case situation. Also, information will be needed on what Metro would do if this situation did, in fact, develop to prevent significant impairment of the water quality in the Misema River, Boston Creek and downstream waterbodies at any time in the future where this scenario could occur. Polluted Groundwater Remediation. Metro should develop a well-defined comprehensive set of remediation approaches that can be used to remediate off-site contaminated groundwaters to the maximum extent possible. It should be understood that it may not be possible to remediate offsite MSW leachate-polluted groundwaters so that wells that pump such waters can ever again be considered safe for domestic and some other uses. It will be essential, however, that Metro have well developed contingency plans in place to remediate the polluted groundwaters to the maximum extent possible and, most importantly, to stop further spread of polluted groundwaters off-site from the Adams Mine Site property. These plans should be developed now so they can be reviewed for their adequacy with respect to implementability, reliability and funding. At the time that Metro finds off-site leachate-polluted groundwaters, Metro will need to begin to develop an effective on-site groundwater remediation program to stop further off-site groundwater pollution. This program may have to include exhumation (removal) of the wastes from the Adams Mine Site Landfill if the on-site remediation programs cannot stop off-site pollution of the groundwaters. Adequate funding for groundwater remedial activities, including the mining of wastes from this landfill, should be available for both the off-site and on-site polluted groundwater remediation programs. This funding should be established in a dedicated trust fund derived from disposal fees that will be of sufficient magnitude to address all plausible, worst-case failure scenarios and groundwater remediation needs. The planning for the use of these funds should make them available ad infinitum. If at some time hundreds to a thousand or more years from now it is found that no groundwater pollution has occurred and the landfill and associated leachate-polluted groundwaters are no longer a threat to cause off-site groundwater pollution, then these funds could be returned to Metro for other uses. In judging whether off-site groundwater pollution occurs, it will be important that no use be made of the MOEE Reasonable Use Policy which allows contamination of groundwaters by 14

15 leachate-derived constituents up to about 25% of the Ontario Drinking Water Objective for health-related parameters and 50% of the Objective for non-health-related parameters. This Policy ignores the potential threat that the unregulated organics present in MSW leachate represent to the health and welfare of those who use such waters contaminated to this level. For the purposes of developing the Adams Mine Site Landfill, the need for remediation of polluted groundwaters should be based on finding any Adams Mine Site MSW Landfill leachate-derived constituents in off-site groundwaters. Landfill Gas. Metro and its consultants assert in the draft Overview Document that the landfill gas collection and management system will be operated for a period of approximately 30 years after site closure. While the Overview Document provides an extensive glossary of waste management terms, it fails to define closure which is one of the most important terms associated with developing a landfill. In the waste management field, the closure of a landfill means the termination of receipt of waste and the installation of a cover on the landfill. It is the author's understanding that closure will be completed in about 20 years after the site (3 pits) begins operations. There will be closure of some of the pits during this period since they will stop receiving waste earlier than the other pits. If the conventional use of site closure is applicable to the Adams Mine Site Landfill, it is inappropriate for Metro's consultants to claim that it will be possible to stop landfill gas management 30 years after site closure. In fact, this is shorter than the period of landfill gas generation at the Adams Mine Site Landfill projected by Metro's consultants. The contaminating lifespan is a product of the interaction of water percolating into and through the waste and landfill gas generation rates and duration. Metro's consultants have apparently not adequately considered the problems that will be encountered in having the moisture in the landfill interact with the waste that is contained within the crushed, but not shredded, garbage bags. These bags of waste will become significant impediments to moisture entering the waste and thereby could lead to leachate and gas production. At this time Metro has not given adequate reliable consideration to the potential benefits associated with the shredding of the MSW landfill waste in shortening the contaminating lifespan for both leachate and landfill gas production. This is an area that Metro needs to reexamine since it could be an important factor in influencing whether this landfill should be developed, especially in light of the MOEE regulations that require that the contaminating lifespan be less than the service life of any non-maintainable structural components for leachate and gas management. As long as the plastic garbage bags are allowed to remain essentially intact, the contaminating lifespan of this landfill will be determined to a considerable extent by the ability of the moisture that enters the waste to interact with the garbage located in these bags. These bags will decompose slowly and could greatly extend the period of time that landfill gas and leachate production occur where they would be threats to groundwater quality and the use of the region near the Adams Mine Site Landfill through gaseous emissions. At the TFA - PLC workshop on December 9, 1995, Metro's consultants indicated that a change in the proposed design of the landfill has occurred in which the circumferential vertical liner near the upper part of the landfill has been replaced by a granular drainage layer. Rather than trying to block the lateral transport of leachate through this region, Metro's consultants propose to allow 15